E field in a coax

[TMD]

I asked this ages ago and got a response refering to surface integrals and Gauss's Law and good stuff like that. Well I struggled and can't cast my mind back 25+ years to figure that out again.

So I'll ask again, and hope someone can respond (preferably with an equation or two).


What are the expressions for electric field strength in a coax having two dielectrics?

 

[GOTWW]

let r1= inner conductor radius

r2, e2 = inner dielectric radius & dielectric constant

& r3, e3= outer conductor radius and e3 fills between r2 & r3.

assume only charge is located on center conductor

Q= 2*pi*r1*rho_s = total charge per unit length

Then e1 = Q/(2*pi*e2*r) r1<r<r2
Q/(2*pi*e3*r) r2<r<r3

 

[GOTWW]

check out

http://www.microwaves101.com/encyclopedia/caldualcoax.cfm